1. Field of the Invention
The present invention relates, in general, to vehicle power seat adjusters and, more specifically, to memory systems for vehicle power seat adjusters which reposition the seat to a stored memory position.
2. Background Art
Power seat adjusters are a popular option on many automotive vehicles and are frequently offered as standard equipment on higher priced vehicles. Such power seat adjusters are primarily used on the driver's seat and, sometimes, on the front passenger seat of the vehicle to provide selective horizontal fore and aft and vertical movement of the seat as well as seat back recliner movement to accommodate occupants of different size and height as well as to provide a comfortable seating position to suit each occupant's preference.
Such power seat adjusters typically carry a seat support frame which supports the seat bottom and sometimes the seat back of a vehicle seat. The seat support frame is mounted on first and second, spaced track assemblies, each formed of an upper track which is connected to the seat support frame and which is slidably mounted on a lower track anchored to the vehicle floor. A drive mechanism typically includes a bi-directional electric motor which rotates a pair of drive shafts extending outward from the motor to a gear assembly or box mounted on each upper track. In one arrangement, each gear box rotates a lead screw extending longitudinally below each upper track. A drive block is fixedly mounted to each lower track and threadingly receives the lead screw to cause reciprocal, horizontal movement of the upper track and the attached seat support frame upon selective energization of the drive motor and the drive shafts.
Similar drive mechanisms are provided for vertical (up and down) adjustment of the seat support frame and, in a seat adjuster having a seat recliner adjustment mechanism, for angularly adjusting the position of the seat back with respect to the seat bottom. The vertical drive mechanism may include separate front and rear edge seat adjustment drive mechanisms for selectively tilting the front and rear edges of the seat bottom independent of each other as well as simultaneously to raise and lower the entire vehicle seat or, in some applications, only the seat bottom or cushion.
Each vertical and recliner drive mechanism also includes a drive motor having a rotatable output shaft connected to a gear assembly either directly in the case of the front and rear vertical drive mechanisms or by means of two shafts extending from a single motor to separate gear assemblies mounted on each upper track or on the seat support frame in the case of a seat recliner drive mechanism.
Control for each drive motor is provided by a manually operable, two position, center neutral switch which is activated by a user and held in one position to supply current to the selected drive motor to rotate the output shaft of the motor in the desired direction to effect repositioning of either the horizontal, vertical and/or seat recliner drive mechanisms of the seat.
It is also known to provide the driver and/or passenger seat with memory capability to automatically move the seat adjuster to one of one or more memory or recall positions which are preset by an occupant. Such seat adjusters with memory control capability have also included a so-called "easy entry" position in which the seat adjuster, upon activation of pushbutton, is moved to a position permitting easy ingress and egress to and from the seat.
In such power seat adjusters, the seat is repositioned under user control or automatically to a recall memory position, or to or from an "easy entry" position at the same, single speed. While such a single speed is acceptable for manual operation of the seat which generally requires only small incremental movements, the generally slow speed of the drive motor for memory seat position recall or movement to or from the "easy entry" position is unsatisfactory due to the length of time required for the seat adjuster to reach the "easy entry" position or to return to the memory position when the driver or passenger is ready to enter or leave the vehicle.
Thus, it would be desirable to provide a vehicle power seat adjuster with last seat position memory recall and an easy entry position permitting easy ingress and egress to and from the seat which overcomes the deficiencies of previous devices memory control seat adjusters. It would also be desirable to provide a vehicle power seat adjuster with memory position recall and an easy entry memory position in which the drive motor(s) are capable of multiple speed operation for use in quickly repositioning the seat adjuster to and/or from the "easy entry" position.